Caption: Scanning electron micrograph (SEM) of Corynebacterium tuberculostearicum, Gram-positive, rod-or club-shaped bacterium (prokaryote). C. tuberculostearicum is a non-motile, non-spore-forming, lipophilic, aerobic to facultatively anaerobic bacterium whose cells are pleomorphic. They do not form spores or branch as do the actinomycetes, but they have the characteristic of forming irregular shaped, club-shaped cells in normal growth. It was named C. tuberculostearicum in part because the fatty acid profile of this organism contains tuberculostearic acid. With the exception of Corynebacterium diphtheria (which causes diphtheria), species in the genus Corynebacterium do not typically cause disease, and are a part of normal human skin flora. Magnification: x3,000 when shortest axis printed at 25 millimetres.